TL;DR: 🟢 Positive — a nonselective extracorporeal blood purification device significantly reduced cardiac-surgery-associated AKI (28.4% vs 39.7%, P=0.01), though most secondary endpoints were unchanged.
1. Publication
- Title: Extracorporeal Blood Purification and Acute Kidney Injury in Cardiac Surgery: The SIRAKI02 Randomized Clinical Trial
- Acronym: SIRAKI02
- Year & Journal: JAMA, published October 9, 2024 (332(17):1446-1454)
- Citation: Pérez-Fernández X, Ulsamer A, Cámara-Rosell M, et al; SIRAKI02 Study Group. JAMA. 2024;332(17):1446-1454. doi:10.1001/jama.2024.20630
2. Context & Rationale
Background: Cardiac surgery-associated AKI (CSA-AKI) remains a major concern after cardiopulmonary bypass; extracorporeal blood purification devices have been proposed to reduce inflammatory mediators driving AKI, but evidence on a specific nonselective adsorptive membrane during CPB was limited.
Research Question/Hypothesis: In high-risk cardiac surgery patients, does a nonselective extracorporeal blood purification (EBP) device connected to the CPB circuit reduce CSA-AKI incidence in the first 7 days compared with standard care?
3. Design & Methods
- Study Type: Randomized clinical trial
- Setting & Centers: Spain (Hospital Universitari de Bellvitge and collaborating centers)
- Population: 343 adults (mean age 69y, 119 female) undergoing nonemergent, high-risk cardiac surgery (double/triple valve replacement, CABG+valve, or ascending aortic replacement+CABG/valve)
- Intervention: Nonselective EBP device (acrylonitrile-sodium methallylsulfonate/polyethyleneimine membrane, oXiris) connected to CPB circuit
- Comparator: Standard care (no EBP)
- Statistical Power & Follow-Up: Primary: CSA-AKI incidence within first 7 postoperative days.
4. Key Results
343 patients randomized.
Outcome | EBP | Standard Care | Effect Size | p-value | Notes |
CSA-AKI within 7 days (primary) | 28.4% | 39.7% | Adjusted diff 10.4pp | 0.01 (adjusted); 0.03 (unadjusted) | Significant reduction |
Most secondary/exploratory endpoints | No significant difference | No significant difference | — | — | Benefit limited to primary AKI-incidence endpoint |
Subgroup signal (CKD, diabetes, hypertension, LVEF<40%, BMI<30) | Greater reduction | — | — | — | Larger AKI-risk reduction in these high-risk subgroups |
5. Internal Validity Assessment
Randomized trial with a clear, statistically significant primary result. Overall: Moderate-to-strong — significant reduction in the primary AKI-incidence endpoint, though most secondary/exploratory endpoints showed no significant difference — an important limitation on the breadth of demonstrated benefit; a Critical Care commentary ("RECCAS, REMOVE, and SIRAKI02: discrepant outcomes") notes divergent results across similar EBP trials, attributed to differences in adsorption mechanisms between devices.
6. External Validity Assessment
Spanish, high-risk nonemergent cardiac surgery population — relevant to centers performing complex cardiac surgery with CPB and access to this specific EBP device/membrane.
7. Strengths & Limitations
Strengths: Addresses a genuine, high-morbidity complication (CSA-AKI) with a statistically significant primary result; subgroup signals (CKD, diabetes, reduced LVEF, lower BMI) are biologically plausible and consistent with a targeted, high-risk-patient benefit.
Limitations: Most secondary/exploratory endpoints (beyond the primary AKI-incidence measure) showed no significant difference; discrepant results compared with other EBP device trials (RECCAS, REMOVE) using different adsorption mechanisms; requires specific device availability.
8. Interpretation & Practice Impact
Supports considering nonselective EBP specifically for high-risk cardiac surgery patients (CKD, diabetes, reduced LVEF, lower BMI) to reduce early CSA-AKI incidence, though the benefit did not extend to most other measured secondary/exploratory outcomes — an important caveat on the breadth of clinical impact.
9. Controversies & Subsequent Evidence
An accompanying JAMA commentary ("Impact of Adsorptive Blood Purification on Kidney Outcomes," Kwong, Liu) and a subsequent Critical Care commentary specifically address the discrepancy between SIRAKI02's positive result and other EBP trials' (RECCAS, REMOVE) more neutral findings, attributing this to differences in the specific adsorption mechanism/membrane used — an important caution against generalizing SIRAKI02's positive result to all EBP devices as a class.
10. Summary & Executive Takeaway
Summary: SIRAKI02 randomized 343 high-risk cardiac surgery patients to a nonselective EBP device during CPB or standard care. CSA-AKI within 7 days was significantly reduced (28.4% vs 39.7%, adjusted difference 10.4 percentage points, P=0.01), with greater benefit in patients with CKD, diabetes, reduced LVEF, or lower BMI, though most secondary/exploratory endpoints showed no significant difference.
Overall Takeaway: A specific nonselective EBP device meaningfully reduces early CSA-AKI incidence in high-risk cardiac surgery patients, particularly those with additional comorbidity risk factors — but this benefit was limited to the primary AKI-incidence endpoint, and device-specific adsorption mechanism appears to matter given discrepant results across similar EBP trials.
11. Bibliography
- Kwong YD, Liu KD. Impact of Adsorptive Blood Purification on Kidney Outcomes [editorial]. JAMA. 2024;332(17):1430.
- RECCAS trial. Removal of cytokines during cardiac surgery. Crit Care. 2024;28(1):406.